Biomedical subjects

S M Sadrzadeh

Publications and source records attributed to S M Sadrzadeh.

At least 19 recordsLinked to original sources

PubMed2000

Human plasma and tirilazad mesylate protect stored human erythrocytes against the oxidative damage of gamma-irradiation.

Transfusion-associated graft-versus-host disease (TA-GVHD) is a serious condition that under certain circumstances can be lethal in immunosuppressed patients. The risk of TA-GVHD can be reduced in this population by gamma irradiation (gammaRad) of blood components. gammaRad results in production of reactive oxygen species which can damage red blood cells (RBC). Tirilazad mesylate (TM) is a member of the 21-aminosteroids (Lazaroids) family and is a powerful antioxidant. We investigated the ability of TM and human plasma (which contain powerful antioxidants) to protect stored human RBC against the oxidative damage of gammaRad. Fresh intact packed RBC obtained from the normal donors, with and without autologous plasma or TM (0.05 mg mL-1 RBC), were exposed to gammaRad (50 Gy) and stored for 28 days at 4 degrees C. Oxidative damage was assessed by osmotic fragility at 65 mM NaCl concentration (expressed by percentage haemolysis in 65 mM NaCl solution) and lipid peroxidation (measured by thiobarbituric acid reactive substances, TBARS). Our results showed that storage and irradiation of untreated intact RBC increased the osmotic fragility at 65 mM NaCl concentration (65.8 +/- 1.3 vs. 51.20 +/- 0.87% haemolysis; irradiated vs. controls, respectively; P = 0.002) and lipid peroxidation (TBARS = 4.47 +/- 0. 12 vs. 3.45 +/- 0.09 microM L-1 RBC; irradiated vs. controls, respectively; P = 0.001). TM protected the intact RBC against radiation-induced haemolysis (35.8 +/- 5.0 vs. 65.8 +/- 1.3% haemolysis; treated vs. untreated irradiated RBC, respectively; P = 0.02) and lipid peroxidation (TBARS = 2.91 +/- 0.2 vs. 4.47 +/- 0.12 microM L-1 RBC; treated vs. untreated irradiated RBC, respectively; P = 0.005). Addition of autologous plasma to packed RBC significantly reduced the extent of radiation-induced haemolysis by more than six-fold (12.45 +/- 0.26 vs. 65.8 +/- 2.2% haemolysis; irradiated RBC with versus without plasma, respectively; P = 0.0001). In conclusion, these results show that irradiation and storage of blood damages RBC via oxidative processes and addition of autologous plasma and/or TM protects RBC against such damage and possibly enhances their storage and survival.

Antioxidants↗

PubMed2000

Hydroxy-urea protects erythrocytes against oxidative damage.

Hydroxy-urea (OH-U) is used to treat sickle cell anemia by increasing hemoglobin fetal-fraction. It has been suggested that the sickle cell mutations lead to the formation of unstable HbS and release of iron, which can result in lipid peroxidation (LPO), and eventual cell damage. Since oxidative processes might be involved in pathogenesis of sickle cell disease, we investigated the antioxidant property of OH-U in a red blood cell (RBC) model. Intact RBCs or RBC membranes were exposed to t-butyl hydroperoxide (t-BHP, 0.75 mM) or iron (ferrous sulfate; 100 microM) at 37 degrees C for 60 min in the presence or absence of OH-U (1.25 mM). The extent of oxidative damage was measured by LPO (as thiobarbituric acid reactive substances, TBARS), hemoglobin oxidation (as percent of methemoglobin, metHb %), and decrease in the activities of membrane-bound Na+/K+-ATPase and Ca2+-ATPases. Our results show that OH-U inhibited t-BHP-induced LPO in fresh RBC membranes significantly (P <0.01). OH-U significantly inhibited t-BHP-mediated LPO (P <0.01) and metHb formation (P <0.01) in intact RBC. Also, OH-U inhibited iron-induced LPO and metHb formation in intact RBC (P <0.01). In addition, OH-U blocked t-BHP-mediated changes in membrane ATPase activities. Furthermore, OH-U blocked iron-mediated hydroxyl radical generation in a dose-dependent fashion. In conclusion, the observed antioxidant properties of OH-U might contribute to its therapeutic action in sickle cell disease.

Antioxidants↗

PubMed1998

The 21-aminosteroid 16-desmethyl tirilazad mesylate prevents necroinflammatory changes in experimental alcoholic liver disease.

We investigated the potential of 16-desmethyl tirilazad mesylate, a member of 21-aminosteroids, to ameliorate alcohol-induced liver injury. Four groups (five rats/group) of male Wistar rats were studied. One group of rats was fed fish oil and ethanol (FE) for 4 weeks, and a second group received isocaloric amounts of dextrose instead of ethanol (FD). The third (FE-LAZ) and fourth (FD-LAZ) groups received the addition of 10 mg/kg/day of 16-desmethyl tirilazad mesylate (U74389) daily via intragastric tube. Liver samples were analyzed for histopathology, nonheme iron, lipid peroxidation and levels of mRNA for tumor necrosis factor-alpha (TNF-alpha) and cyclooxygenase-2 (COX-2). Concentrations of endotoxin and 8-isoprostane were measured in plasma. Membrane ATPases were measured in isolated membrane red cells. FE rats developed fatty liver, necrosis and inflammation. Treatment with the 21-aminosteroid resulted in prevention of necroinflammatory changes, but the degree of fatty liver was unchanged. The absence of necroinflammatory changes in the FE-LAZ group was accompanied by a decrease in levels of nonheme iron, lipid peroxidation, TNF-alpha mRNA and COX-2 mRNA. Ethanol administration decreased membrane Ca(++)-ATPase and calmodulin-stimulated Ca(++)-ATPase, and the decrease was reversed by 21-aminosteroid treatment. The data indicate that the improvement in the degree of necrosis and inflammation in the rats treated with the 21-aminosteroid may be explained, at least in part, by reduced levels of proinflammatory stimuli such as lipid peroxidation, TNF-alpha and COX-2. Membrane stabilization may also, by reducing lipid peroxidation, play an additional role in preventing liver injury.

Adenosine Triphosphatases↗

PubMed1997

Radiation-induced red cell damage: role of reactive oxygen species.

BACKGROUND: Cellular blood components are irradiated to prevent graft-versus-host disease in transfusion recipients at risk for this syndrome. Because gamma radiation can result in the production of reactive oxygen species, the role of reactive oxygen species was investigated in radiation-induced red cell damage. STUDY DESIGN AND METHODS: Whole blood from normal donors was exposed to various doses of t-butyl hydroperoxide (0-1 mM) and/or to gamma-radiation (0-50 Gy). Oxidative damage was assessed by the extent of lipid peroxidation (measured by thiobarbituric acid-reactive substances [TBARS]) and hemoglobin oxidation. Fresh blood was divided into three parts-one initially irradiated and stored, another stored with portions irradiated weekly, and a third stored without irradiation. TBARS and hemoglobin oxidation were measured weekly. RESULTS: As expected, t-butyl hydroperoxide induced TBARS formation and hemoglobin oxidation in a dose-dependent fashion. The gamma-radiation not only increased hemoglobin oxidation and TBARS formation, but also enhanced the t-butyl hydroperoxide effect on red cells. Red cell storage increased TBARS generation and hemoglobin oxidation in a time-dependent fashion. When radiation was administered either initially or after weekly storage, TBARS production and hemoglobin oxidation were increased over that measured in unirradiated paired controls. CONCLUSION: Gamma radiation at clinically used doses increases lipid peroxidation and hemoglobin oxidation in human red cells. The effect of gamma-radiation is accentuated by blood storage and induces damage independent of time of storage.

Antioxidants↗

PubMed1997

The long-acting parenteral iron chelator, hydroxyethyl starch-deferoxamine, fails to protect against alcohol-induced liver injury in rats.

We studied the effect of the long-acting parenteral iron chelator, hydroxyethyl starch deferoxamine (HES-DFO) on liver nonheme iron, lipid peroxidation and pathologic changes in the liver in the intragastric feeding rat model for alcoholic liver disease. Male Wistar rats (225-250 g) were fed liquid diet and ethanol for 2 months. In control pair-fed animals, ethanol was isocalorically replaced by dextrose. Two additional groups of animals (dextrose and ethanol fed) received HES-DFO (25 mg deferoxamine equivalents/kg, three times a week). The blood ethanol level in the ethanol-fed animals was maintained between 150 and 350 mg/dl. For each animal, the levels of hepatic nonheme iron, lipid peroxidation and pathologic changes were evaluated. Ethanol administration caused fatty liver, necrosis and inflammation. Addition of HES-DFO to the ethanol diet increased the severity of pathologic changes, particularly necrosis and inflammation. The nonheme iron in alcohol-fed animals was significantly higher (18.3 +/- 4.3 microg liver) than in pair-fed dextrose controls (12.5 +/- 1.5 microg, P < .05). Addition of HES-DFO significantly increased nonheme iron levels in the dextrose-fed rats (17.1 +/- 2.0 microg/g, P < .02) but not in ethanol-fed rats (20.0 +/- 2.0). Ethanol increased levels of conjugated dienes; these levels were not altered by HES-DFO. The most significant observations in this study were: 1) the higher hepatic nonheme iron content in ethanol-fed rats compared with pair-fed dextrose controls; 2) the absence of changes in hepatic nonheme iron levels or lipid peroxidation in ethanol-fed groups treated with HES-DFO; and 3) the worsening of liver injury in ethanol-fed rats by HES-DFO.

Alanine Transaminase↗

PubMed1996

Elevated plasma levels of hyaluronic acid indicate endothelial cell dysfunction in the initial stages of alcoholic liver disease in the rat.

BACKGROUND/AIMS: We used the intragastric feeding rat model for alcoholic liver disease to evaluate the relationship between morphologic and functional indicators of endothelial cell dysfunction. METHODS: Twelve groups of rats (4-5 rats/group) were fed the following diets: saturated fat and dextrose (SD), saturated fat and ethanol (SE), corn oil and dextrose (CD), corn oil and ethanol (CE). Four of the 12 groups were sacrificed at 2 weeks, four groups at 4 weeks and remaining four groups at 8 weeks. The following were evaluated at sacrifice: pathologic changes in the liver, endothelial cell proliferation using a monoclonal antibody to proliferating cell nuclear antigen, factor VIII-related antigen staining of endothelial cells in liver, plasma endotoxin, hyaluronan and prostaglandin F2 alpha. RESULTS: Only CE rats at 4 and 8 weeks showed pathologic changes. The plasma levels of HA were significantly higher in the CE groups compared to the other groups at all time intervals studied. In the CE rats, a significant correlation was obtained between plasma endotoxin and hyaluronan (r = 0.84, p < 0.01). Endotoxin levels also correlated significantly with the number of G1/S arrested hepatic sinusoidal endothelial cell (r = 0.61, p < 0.05). A role for prostaglandin F2 alpha, in causing endothelial dysfunction, was suggested by a significant correlation between plasma hyaluronan and prostaglandin F2 alpha levels (r = 0.95, p < 0.01). Positive factor VIII related antigen staining of hepatic endothelial cells was seen in rats with high plasma hyaluronan levels. CONCLUSION: We propose that endotoxin, mediating part of its effect through prostaglandin F2 alpha, plays a role in hepatic sinusoidal endothelial cell G1/S arrest. This morphologic change, associated with increased plasma hyaluronan levels, precedes capillarization in this model of alcoholic liver injury.

Animals↗

PubMed1996

Medium chain triglycerides and vitamin E reduce the severity of established experimental alcoholic liver disease.

Lipid peroxidation may be important in the pathogenesis of alcoholic liver injury. We investigated the potential of medium chain triglycerides and vitamin E to decrease lipid peroxidation and reverse established alcoholic liver injury. Four groups (five rats/group) of male Wistar rats were studied. Rats in group 1 were fed a fish oil-ethanol diet for 6 weeks. Rats in groups 2, 3 and 4 were fed the fish oil-ethanol diet for 6 weeks before being switched to fish oil-dextrose (group 2), fish oil-dextrose plus vitamin E (group 3) or medium chain triglycerides-dextrose (group 4) diets for 2 weeks. Liver samples were analyzed for histopathology, lipid peroxidation, fatty acid composition and cytochrome P450 2E1 activity. By 6 weeks, all rats developed fatty liver, inflammation and necrosis. After switching to the dextrose-containing diets, there was minimal histologic improvement in group 2, moderate improvement in group 3 and near normalization of the histology in group 4. Histologic improvement was associated with decreased lipid peroxidation and cytochrome P450 2E1 activity. Higher levels of polyunsaturated fatty acids were seen in groups 2 and 3 than in group 4. Our results indicate that a diet enriched in saturated (group 4) but not polyunsaturated (group 2) fatty acids effectively reverses alcoholic liver injury. Treatment with vitamin E also led to histologic improvement. These effects may be explained, at least in part, by down-regulation of lipid peroxidation. Other effects of medium chain triglycerides, such as their propensity for oxidation rather than esterification, may also be important.

Animals↗

PubMed1995

Dietary saturated fatty acids: a novel treatment for alcoholic liver disease.

BACKGROUND & AIMS: Lipid peroxidation may be important in the pathogenesis of alcoholic liver injury. The purpose of this study was to determine whether a saturated fatty acid-based therapy (palm oil) could decrease lipid peroxidation and alcoholic liver injury during ethanol withdrawal. METHODS: Three groups of male Wistar rats (5 rats/group) were studied. Rats in group 1 were fed a fish oil-ethanol diet for 6 weeks; rats in groups 2 and 3 were fed a fish oil-ethanol diet for 6 weeks before treatment with fish oil-dextrose (group 2) or palm oil-dextrose (group 3) for 2 weeks. Liver samples were analyzed for histopathology, lipid peroxidation, fatty acid composition, cytochrome P450 2E1 activity, and tocopherol levels. RESULTS: By 6 weeks, all rats had developed fatty liver, inflammation, and necrosis. Group 2 showed minimal histological improvement, whereas group 3 showed near normalization of the histology. The improvement in group 3 was associated with decreased lipid peroxidation and P450 2E1 activity. Higher levels of omega-3 fatty acids were detected in group 2 than group 3. Tocopherol levels were similar among the groups. CONCLUSIONS: A diet enriched in saturated but not unsaturated fatty acids reversed alcoholic liver injury. This effect may be explained by down-regulation of lipid peroxidation.

Animals↗

PubMed1995

Nitric oxide production in experimental alcoholic liver disease in the rat: role in protection from injury.

BACKGROUND & AIMS: Regulation of blood flow and oxygen supply are important pathogenetic factors in alcoholic liver disease. Because nitric oxide may have an important role, its effects on alcoholic liver injury were investigated. METHODS: Rats were fed ethanol intragastrically with either saturated fat or corn oil. Spontaneous production of NO by liver nonparenchymal cells was compared in the two dietary groups. Two additional groups of rats fed corn oil and ethanol were treated with either an NO inhibitor (L-NAME) or supplemented with L-arginine. Liver pathology and plasma NO production were evaluated. RESULTS: In the corn oil and ethanol group, a progressive decrease in liver nonparenchymal cell NO production and increased plasma NO levels were associated with liver injury. Reduced nicotinamide adenine dinucleotide phosphate diaphorase staining showed increased centrilobular staining of hepatocytes in the corn oil and ethanol group and L-NAME-treated group. Moreover, L-NAME increased the severity, whereas L-arginine supplementation completely prevented liver injury. In the saturated fat and ethanol group, in which there was no liver injury, the levels of NO2- in nonparenchymal supernatant were 5-10-fold higher than in the corn oil and ethanol group. CONCLUSIONS: Decreased NO production by nonparenchymal cells may contribute to liver injury in ethanol-fed rats, and the compensatory increase in hepatocyte NO production may contribute to centrilobular liver injury.

Analysis of Variance↗

PubMed1995

Heat-shock gene expression in alcoholic liver disease in the rat is related to the severity of liver injury and lipid peroxidation.

To evaluate the relationship between heat-shock gene expression and the severity of pathologic liver injury and lipid peroxidation in experimental alcoholic liver disease, we used the intragastric-feeding rat model. Six groups of male Wistar rats weighing between 225 and 250 g were fed liquid diets containing different dietary fats (saturated fat, corn oil, and fish oil) and ethanol or dextrose for 1 month. Pathologic injury, mRNA and protein levels of HSP70, microsomal conjugated dienes, and hydrogen peroxide were evaluated at sacrifice. Fish oil-ethanol fed rats developed the most severe injury, while the saturated fat-ethanol group showed no liver injury. The highest levels of HSP70 mRNA were seen in the fish oil-ethanol group. There was no difference in HSP70 protein levels between the groups. The levels of HSP70 mRNA correlated significantly with microsomal conjugated dienes (r = 0.87, P < 0.01) and hydrogen peroxide (r = 0.90, P < 0.01). Increased centrilobular HSP70 expression was seen in rats showing liver injury. The close relationship seen between oxidant stress and HSP70 mRNA but not protein suggest that the binding of HSP70 protein to other damaged proteins reduces free HSP70 protein leading to increased HSP70 expression. HSP70 expression may also be a cellular adaptive response to ethanol-induced oxidative stress.

Animals↗

PubMed1995

Effect of type of dietary fat and ethanol on antioxidant enzyme mRNA induction in rat liver.

We carried out a study to relate the effect of the type of dietary fat and ethanol on antioxidant enzyme mRNA levels in liver in the intragastric feeding rat model. Different types of dietary fat were administered [saturated fat (SE), corn oil (CE) and fish oil (FE)] with ethanol to induce varying severities of liver injury. Ethanol-fed rats were pair-fed with dextrose-fed controls that received isocaloric amounts of dextrose. All animals were killed at 1 month and the following studies were carried out: evaluation of severity of pathologic liver injury, mRNA quantitation for catalase, glutathione peroxidase (GPx), and manganese superoxide dismutase (MnSOD), microsomal conjugated dienes, and hydrogen peroxide. SE animals had no liver injury, FE animals had severe liver injury, and CE animals had moderate liver injury. Ethanol induced GPx mRNA in all dietary groups, with the highest levels seen in the FE group. The pattern of catalase mRNA induction was similar to that of GPx mRNA. In contrast, MnSOD mRNA was decreased compared to controls in animals that developed pathologic liver injury, i.e., CE and FE groups. A positive correlation was seen between conjugated diene levels and GPx mRNA (r = 0.88, P < 0.01) and catalase mRNA. The similar slopes for the relationship between conjugated dienes and catalase in the fish oil and non-fish oil groups indicate that the same degree of lipid peroxidation increases catalase mRNA to a greater degree in fish oil-fed rats. A positive correlation was also seen between catalase mRNA and H2O2 (r = 0.95, P < 0.001).

Animals↗

PubMed1995

High-dose vitamin E supplementation has no effect on ethanol-induced pathological liver injury.

The effect of alpha-tocopherol (alpha-T) supplementation on ethanol-induced liver damage was studied. The intragastric feeding rat model was used in this study. Both normal and alpha-T supplemented animals (3125 IU/kg body weight) were fed liquid diet and ethanol for 1 mo. In pair-fed animals, ethanol was isocalorically replaced by dextrose. The blood ethanol level in the ethanol-fed groups was between 150 to 350 mg/dl. Lipid peroxidation was assessed by measuring liver thiobarbituric acid reactive substances (TBARS) and conjugated dienes. Liver damage was assessed by light microscopy. Overall, chronic ethanol treatment resulted in increase in TBARS and conjugated dienes in both normal (60% and 35%, P < .01, respectively) and alpha-T-supplemented groups (50% and 47%, P < .01, respectively). In animals receiving either dextrose or ethanol and regular diet, there was a significant inverse correlation between liver alpha-T and TBARS (r = 0.88, P < 0.01) and conjugated dienes (r = -0.75, P < .05). In contrast, in the vitamin E-supplemented rats, a significant positive correlation was observed between liver alpha-T, TBARS (r = 0.78, P < .01) and conjugated dienes (r = 0.87, P < .01). Of major significance is that alpha-T supplementation had no effect on ethanol-induced pathological changes in the liver. In conclusion, these results show that in the intragastric feeding model, alpha-T supplementation had no protective effect on ethanol-induced liver damage.

Animals↗

PubMed1994

Eicosanoid production in experimental alcoholic liver disease is related to vitamin E levels and lipid peroxidation.

We investigated the association between vitamin E, lipid peroxidation and eicosanoid production in experimental alcoholic liver injury. We used the intragastric feeding rat model in which animals were fed corn oil and ethanol (CO+E) and corn oil and dextrose (CO+D) for 2 and 4 week periods. At sacrifice, we measured plasma levels of alpha-tocopherol, 8-isoprostane, thromboxane B2 (TXB2) and 6-ketoprostaglandin F1 alpha (6-KetoPGF1 alpha). Animals fed CO+E had significantly lower concentrations of alpha-tocopherol and higher concentrations of 8 isoprostane at both 2 and 4 weeks. a significant inverse correlation was seen between alpha-tocopherol concentrations and the TXB2: PGF1 alpha ratio (r = 0.72, p < 0.01). A positive correlation was seen between the TXB2: PGF1 alpha ratio and 8 isoprostane levels (r = 0.84, p < 0.001). These results suggest that vitamin E depletion and enhanced lipid peroxidation may affect eicosanoid metabolism in experimental alcoholic liver disease in such a way so as to increase the thromboxane to prostacyclin ration.

Animals↗

PubMed1994

Enhancement of hemin-induced membrane damage by artemisinin.

Artemisinin is an effective antimalarial agent, and its action on the malarial parasite is suggested to be mediated by oxidative processes. Since malarial parasites contain a high concentration of hemin, and hemin may induce the formation of reactive oxygen species, we investigated the interaction of artemisinin, iron and hemin. We used erythrocyte membrane-bound Ca2+ pump ATPase (basal) and calmodulin (CaM)-activated Ca2+ pump ATPase as our model. Membranes were incubated with artemisinin in the presence or absence of iron-ascorbate or hemin at 37 degrees for 1 hr. Following incubation, ATPase activity was measured. Our results showed that artemisinin (500 microM) had no effect on ATPase activities. However, artemisinin enhanced the inhibitory effect of iron (50 microM)-ascorbate (500 microM) on ATPase activity (46.3 +/- 3.9 vs 63 +/- 2.1% for basal; 57.2 +/- 2.5 vs 74.8 +/- 2.1% for CaM-activated). Desferrioxamine (DFO, 200 microM) blocked significantly the effect of iron-ascorbate-artemisinin on ATPases (P < 0.01). Hemin inhibited ATPase activity in a concentration-dependent fashion. Artemisinin enhanced hemin (10 microM)-induced inhibition of basal (36.0 +/- 6.0 vs 73.7 +/- 3.0%) and CaM-activated Ca2+ pump ATPase (31.6 +/- 2.8 vs 70.0 +/- 1.5%). Iron chelators (DFO, ferene, 8-hydroxyquinoline, 1,10-phenanthroline, and 1,2-dimethyl-3-hydroxypyrid-4-one) had no effect on artemisinin plus hemin-induced enzyme inhibition. Catalase (2000 U/mL) had a minor effect on the artemisinin-hemin or hemin-mediated effect. Thiourea (1 mM) had no effect. However, superoxide dismutase (500 U/mL) and dithiothreitol blocked artemisinin-hemin or hemin-mediated ATPase inhibition significantly (P < 0.001). In conclusion, these results suggest that, in our model, artemisinin enhances the damage of hemin-induced ATPases via oxidation of thiol groups on the enzymes. Free iron or hydroxyl radical does not seem to be involved. This interaction between artemisinin and hemin may contribute to the antimalarial action of artemisinin against malarial parasites.

Antimalarials↗

PubMed1994

Effect of chronic ethanol feeding on plasma and liver alpha- and gamma-tocopherol levels in normal and vitamin E-deficient rats. Relationship to lipid peroxidation.

The effects of chronic ethanol intake on the levels of alpha-tocopherol and gamma-tocopherol in serum and liver of both vitamin E-deficient and normal rats were studied. An intragastric feeding rat model was used. Both normal and vitamin E-deficient animals were fed a liquid diet and ethanol for 1 month. In pair-fed animals, dextrose was isocalorically replaced by ethanol. The blood ethanol level in the ethanol-fed animals was between 150 and 250 mg/dL. Liver peroxidation was determined by measuring thiobarbituric acid reactive substances (TBARS). Plasma alanine aminotransferase (ALT) was increased by 3-fold in vitamin E-deficient ethanol-fed rats compared with normal ethanol-fed rats. Plasma alpha- and gamma-tocopherol were decreased in the normal ethanol-fed rats by 22.3 and 65%, respectively (P < 0.01). Liver alpha- and gamma-tocopherol were also decreased by 51.7 and 76%, respectively (P < 0.01). Vitamin E-deficient animals had significantly lower mean plasma alpha-tocopherol (5670 vs 530 ng/mL, P < 0.01), and ethanol feeding did not decrease the levels any further. However, ethanol feeding decreased liver alpha- and gamma-tocopherol by 58.5 and 56.5% (P < 0.01), respectively, beyond the already low levels observed in this group. There was an inverse correlation between liver TBARS and liver alpha-tocopherol (r = -0.59, P < 0.05) and gamma-tocopherol (r = -0.65, P < 0.02). Also of significance is that ethanol feeding decreased the plasma and liver gamma-tocopherol more than the alpha-tocopherol in both normal and vitamin E-deficient animals. In conclusion, ethanol feeding markedly decreased both alpha- and gamma-tocopherol in livers of normal and vitamin E-deficient rats, but it only decreased plasma levels of tocopherols in normal rats. The higher ALT in vitamin E-deficient animals and the inverse correlation between TBARS and alpha- and gamma-tocopherol suggest that enhanced lipid peroxidation is associated with greater severity of liver injury induced by ethanol in vitamin E-deficient rats.

Alanine Transaminase↗

PubMed1994

Ethanol-induced suppression of interleukin 1-like activity: reversal by a quinone derivative.

Chronic ethanol intake impairs several parameters of immune function. Since there is evidence that cytokine production by immune cells may contribute to the immunosuppressive effect of ethanol, we examined interleukin 1 (IL1) production by liver non-parenchymal cells (NPC) in ethanol-fed rats. Male Wistar rats (225-250 g) were fed by continuous intragastric infusion. The source of fat was either saturated fat or polyunsaturated fat. In addition, the effect of a quinone compound on IL1 production was assessed. Animals were fed for various periods: 1 week, 2 weeks, 1 month and 2 months. NPC were isolated and stimulated by lipopolysaccharide. IL1 production by NPC and the ratio of stimulated to unstimulated (S:U) IL1 production were evaluated in the different groups and related to the presence of liver injury. As expected, animals fed corn oil and ethanol (CO+E) developed pathologic liver injury, whereas animals fed saturated fat and ethanol (SF+E) had no liver injury. A progressive decrease in the S:U IL1 ratio was seen in the CO+E group over the 8-week period. The ratio in the SF+E group was higher. The quinone compound reversed the suppressive effect of ethanol on IL1 production. In summary, ethanol-induced suppression of IL1 production was modulated by diet and the presence of liver injury. This suppression of IL1 production was reversed by a quinone compound; the exact mechanism for the reversal of this inhibition is unknown.

Animals↗

PubMed1994

Ethanol-induced changes in membrane ATPases: inhibition by iron chelation.

The effect of chronic ethanol intake, with and without an iron chelator, on the activity of rat membrane ATPases was investigated. Using the intragastric feeding model, male Wistar rats (250 g) were fed a liquid diet and ethanol for 1 month. In control pair-fed animals, ethanol was isocalorically replaced by dextrose. In addition to the above groups, two groups of animals (dextrose or ethanol-fed) also received an oral iron chelator (1,2-dimethyl-3-hydroxypyrid-4-one, L1) (25 mg/kg/day for 30 days). The blood ethanol levels were maintained between 150 and 300 mg/dL. Red cells were washed immediately with ice-cold saline, membranes were prepared, and ATPases were measured. The mean Ca2+ pump ATPase in animals fed ethanol was lower than in dextrose-fed controls. In contrast, Na+/K+ pump ATPase was enhanced following chronic ethanol treatment. The addition of L1 to the diet prevented the changes in both the Ca(2+)-ATPase and Na+/K(+)-ATPase in ethanol-fed rats. Although the exact mechanism for the prevention of changes in ATPase activity by L1 is unknown, it is not a result of non-specific interaction between the chelator and membranes. Incubation of purified membranes with different concentrations of L1 for 60 min at 37 degrees had no effect on the activity of the ATPase. In conclusion, chronic intake of ethanol specifically inhibited Ca2+ pump ATPase and enhanced Na+/K(+)-ATPase in rat red blood cell membranes. The iron chelator, L1, corrected both of these ethanol-induced changes.

Alcohol Drinking↗

PubMed1994

Hepatic sinusoidal endothelial cell G1/S arrest correlates with severity of alcoholic liver injury in the rat.

BACKGROUND/AIMS: Capillarization of the hepatic sinusoid occurs in alcoholic liver disease. Because endothelial cell proliferation is relevant to capillarization, we used the intragastric feeding rat model to evaluate the relationship between pathological liver injury and endothelial cell proliferation. METHODS: Male Wistar rats (225-250 g) were fed liquid diets containing corn oil and ethanol for periods ranging between 1 week and 2 months. At the time the rats were killed, the severity of pathological injury and endothelial cell proliferation using anti-rat proliferating cell nuclear antigen/antibody was evaluated. RESULTS: Two distinctly different populations of proliferating sinusoidal lining cells were identified; one population showed relatively weak granular staining consistent with cells arrested at the G1/S boundary. The other population of cells showed strong granular staining of the nucleoplasm and nucleoli (cells in mid to late S phase). A strong correlation (r = 0.85; P < 0.01) was obtained between pathological severity and G1/S-arrested endothelial cells. There was no correlation between cells in S phase. CONCLUSIONS: The presence of an increased number of G1/S-arrested endothelial cells in animals with severe pathological change suggests that stimuli are present for both endothelial cell proliferation and G1/arrest. The identification of these stimuli could lead to a better understanding of the pathogenesis of alcoholic liver disease.

Animals↗